* It is a large tree growing to 20–40 m tall and with a trunk up to 1.8 m diameter, one of the largest North American hardwood trees. The bark is silvery-white, smooth or lightly fissured when young, becoming dark gray and deeply fissured on old trees. The twigs are grayish-yellow, stout, with large triangular leaf scars. The winter buds are slender, pointed, 1–2 cm long, yellowish brown, and resinous. The leaves are large, deltoid (triangular), 4–10 cm long and 4–11 cm broad with a truncated (flattened) base and a 3–12 cm long, the leaf is very coarsely toothed, the teeth are curved and gland tipped, the petiole is flat; they are dark green in the summer and turn yellow in the fall (but many cottonwoods in dry locations drop their leaves early from the combination of drought and leaf rust, making their fall color dull or absent). more...